The best tool to monitor the effectiveness of information security governance is a Balanced Scorecard. A Balanced Scorecard is a performance management tool used to measure the success of an organization's information security governance. It is a strategic planning and management system that helps organizations track and measure the progress of their security initiatives by using a set of metrics across four areas: financial, customer, internal, and learning and growth. This helps organizations to assess their progress and adjust their security strategies to ensure they are meeting their desired objectives.

The results of a risk assessment would best enable an informed decision by senior management when developing a business case to justify an information security investment. A risk assessment will help to identify and prioritize the threats and vulnerabilities that affect the organization's assets and processes, as well as the potential impact and likelihood of occurrence. A risk assessment will also provide a basis for selecting and evaluating the effectiveness of controls to mitigate the risks. According to CISA, developing a business case for security will be based on an in-depth understanding of organizational vulnerabilities, operational priorities, and return on investment1. The information security strategy, losses due to security incidents, and security investment trends in the industry are possible inputs or outputs of a risk assessment, but they are not sufficient to enable an informed decision by senior management. Reference: 1: The Business Case for Security - CISA 2: The Business Case for Security | CISA 3: #HowTo: Build a Business Case for Cybersecurity Investment 4: Making the Business Case for Information Security

Prevention of authorized access is the greatest threat posed by a distributed denial of service (DDoS) attack on a public-facing web server because it prevents legitimate users or customers from accessing the web services or resources, causing disruption, dissatisfaction, and potential loss of revenue or reputation. Execution of unauthorized commands is not a threat posed by a DDoS attack, but rather by a remote code execution (RCE) attack. Defacement of website content is not a threat posed by a DDoS attack, but rather by a web application attack. Unauthorized access to resources is not a threat posed by a DDoS attack, but rather by a brute force attack or an authentication bypass attack. Reference: https://www.isaca.org/resources/isaca-journal/issues/2017/volume-6/the-value-of-penetration-testing https://www.isaca.org/resources/isaca-journal/issues/2016/volume-5/security-scanning-versus-penetration-testing